There are five flexible single master operations roles in the Active Directory infrastructure. Each of them perform specific Active Directory tasks that other domain controllers in the infrastructure are not permitted to perform. These five FSMO roles are divided into two categories based on their operation boundaries:

When we create the first Active Directory forest and the first Active Directory domain, all these FSMO roles will be installed in the domain's first domain controller (obviously; there's no other place). A majority of the Active Directory infrastructures leave the default configuration...